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Study Reveals LED Lights Disrupt Lunar Cycle Sync

9/25/2025

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Summary

Story summary

Since 2010, menstrual cycles are less synchronized with the lunar cycle due to LED lighting and smartphones.
A study of 176 women over 24 years found lunar alignment mainly in January.
Before 2010, cycles clustered around lunar phases; artificial blue light weakened alignment.
The study proposes a "circalunar clock"; Google Trends shows January spikes for "period pain".

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Story summary

Since 2010, menstrual cycles are less synchronized with the lunar cycle due to LED lighting and smartphones.
A study of 176 women over 24 years found lunar alignment mainly in January.
Before 2010, cycles clustered around lunar phases; artificial blue light weakened alignment.
The study proposes a "circalunar clock"; Google Trends shows January spikes for "period pain".